Your question was how to ask for additionally aid.
You can ask, but the schools generally stick to their FA budgets. Many, many students cannot afford to go without financial aid and the schools are aware that a LOT of their applicants don’t have the money to attend, so they may not guarantee to meet need. It doesn’t hurt to ask for a review of your FA application. Have your parents nearby to answer any questions.
Check your safeties.
Or consider the gap year, as was suggested by several posters.
Additionally, the Santa Clara area is very expensive for day to day living costs.